Explanation of the Issue

Degraded tropical landscapes now cover large areas. The nature and extent of these areas varies considerably, with some being so degraded that they have crossed an ecological threshold and been transformed into grasslands. Some of these grasslands are extensive and relatively homogeneous, and contain only a few remnant patches of undisturbed woody vegetation. Other tropical moist forest areas have been less disturbed but have lost their closed canopies and much of their previous structure and biological diversity. Many degraded landscapes now contain a mosaic of grassland and degraded forest together with patches of intact remnant forest. These degraded lands also differ in the extent to which they are occupied and used by human populations. Some are so degraded that only small human populations remain, while others are still heavily used by large numbers of farmers. These differences mean there are no simple prescriptions for restoring degraded tropical landscapes. The approach used in any location must take account of both the ecological and social circumstances present.

Of course, the same could be said of many degraded lands other than those occupied by tropical moist broad-leaved forests. And tropical forests are usually found in environments where plants grow quickly so that the potential for successional development and recovery is relatively rapid. But three particular issues make these ecosystems rather more difficult to restore than most. First is the sheer diversity of plant and animal species usually present in undisturbed tropical moist forests that must be considered if forests are to be restored. Second, very little is known about the ecology of most of these species. Third, the human populations living in most degraded tropical landscapes are often poor and have few resources. Indeed, their poverty may have been part of the reason the lands were degraded in the first place. If restoration is to be successful, it must help overcome this rural poverty. This often means complete biodiversity restoration is rarely achieved over large areas.